package com.jisheng.xb.common;

import java.security.MessageDigest;

/**
 * MD5加密的工具类
 * @author <a href="mailto:wuyingbing@b2bjoy.com">wuyingbing</a>
 *
 */
public class MD5Encrypt {

    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * 对字符串origin以utf-8编码后十六进表示的字符MD5 hash后的16进制表示。
     * @param origin 要hash的字符
     * @return
     */
    public static String encode(String origin) {
        return encode(origin, "utf-8");
    }
    
    /**
     * 对字符串origin采用指定编码后十六进表示的字符MD5 hash后的16进制表示。
     * @param origin 要hash的字符
     * @param charsetname 编码方式
     * @return
     */
    public static String encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
        } catch (Exception exception) {
            return null;
        }
        return resultString;
    }

    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "A", "B", "C", "D", "E", "F" };
    
    public static void main(String[] args) {
		System.out.println(MD5Encrypt.encode("123456"));
	}

}
